The virus that causes AIDS may have evolved in monkeys or apes more than a century ago

By Bryn Nelson, 15:00 PM October 4, 2013

In 1981, two research groups raised an alarm about a mysterious new infection. They reported that it was killing gay men in California and New York. The more scientists looked, however, the more they found signs that the disease might not be so new after all. In fact, it may have evolved almost a century earlier and in another part of the world.

By testing blood and tissue samples that had been stored in labs for years, researchers discovered that the virus had killed a doctor from Denmark in...